I'm taking some college courses, and one of them explicitly suggests to keep maybe-not-okay communications off of email so that "you don't expose your company to risks of litigation."

Ah, I see. So, when discussing ways to ensure cuatomers cannot utilize our warranty process, I'll make sure to do so in ways that are not traceable and won't show up in discovery.

The underlying reason is that employees don't always know what they're talking about, but their nonsense could be useful to the other side in a court case.

The bigger the company, the more speculation there is about stuff people don't actually understand.

The general rule for email, text, and all other communications I've heard is: "Don't write anything that you wouldn't be comfortable seeing on the front page of the New York times."

Heard that first from a US mil commander who once ran for a minor political office like state rep.